Taking prednisone and Benadryl together

The combination of prednisone and Benadryl has not been known to present an adverse reaction. Here’s what you should know.

By Gerardo Sison, Pharm.D. | May 5, 2024

Key takeaways

Prednisone and Benadryl can generally be taken together without interacting, though they may increase side effects like headache and dizziness.
Prednisone is used for inflammatory conditions and allergic reactions, with dosages ranging from 5 to 60 mg daily, depending on the condition.
Benadryl treats allergy symptoms and can be used as an occasional sleep aid, with adult doses typically between 25 and 50 mg every 4 to 6 hours as needed.
Always consult a healthcare professional before combining these medications, especially if you have pre-existing conditions or are taking other medications.

Prednisone and Benadryl are medications often used to treat symptoms of allergic reactions and inflammatory conditions. Prednisone is a corticosteroid that reduces inflammation by suppressing the immune system’s response. On the other hand, Benadryl is a brand-name drug containing diphenhydramine, an antihistamine that blocks the effects of a chemical released during an allergic reaction called histamine.

Patients can generally take Benadryl with prednisone since they work in different ways, and there’s no known significant interaction between them. However, it’s important to be aware that combining these medications may increase the risk of side effects such as headache and dizziness.

Read on to learn more about taking prednisone and Benadryl together.

Benadryl and prednisone: Uses and dosages

You may need to consider the indication behind using prednisone and Benadryl together, as well as their dosage. Prednisone is FDA-approved for treating conditions such as severe allergies, asthma, rheumatoid arthritis, and certain types of cancer. The prednisone dosage depends on the condition being treated but is typically taken as a daily dose of 5 to 60 mg.

Benadryl is commonly used to treat symptoms of allergies and hay fever. It can also be used for occasional motion sickness or trouble sleeping. The dosage of Benadryl varies depending on age and the condition being treated, with typical doses ranging from 25 to 50 mg every 4 to 6 hours as needed for adults.

Can you take Benadryl and prednisone together?

If you’re experiencing an allergic reaction like hives or itching (urticaria), you might wonder if you can use Benadryl and prednisone together. Although prednisone is a prescription corticosteroid that must be used under the guidance of a healthcare provider, Benadryl is an over-the-counter (OTC) antihistamine that is widely accessible.

The combination is not linked to an adverse drug interaction. However, you may want to seek medical advice from trained healthcare professionals who can provide further guidance.

As for taking prednisone with other antihistamines, it’s generally safe to do so, just as with Benadryl. Similarly, other steroids, such as methylprednisolone and prednisolone, may be taken with Benadryl. However, patients should consult healthcare professionals before combining any medications, as these medications don’t come without potential side effects.

What happens if you take prednisone and Benadryl together?

Combining these two medications may carry an increased risk of certain side effects. Some potential side effects include but may not be limited to:

Dizziness
Dry mouth
Blurred vision
Headache
Worsened seizures
Confusion
Constipation

These side effects may be increased, particularly when high doses of prednisone and Benadryl are taken. By being aware of the potential side effects of prednisone and Benadryl and taking necessary precautions, you may be able to safely use prednisone and Benadryl as directed by a healthcare provider.

Although prednisone can cause insomnia or trouble sleeping as a side effect, abruptly stopping the drug may lead to withdrawal symptoms that include excessive fatigue or tiredness. Because Benadryl is known to cause drowsiness as a common side effect, drowsiness may be increased when taking Benadryl after completing a course of prednisone.

When would you need to take Benadryl and prednisone?

There are specific situations in which an individual might take these medications together. For example, during a severe allergic reaction or an instance of anaphylaxis, a healthcare provider might recommend combining these drugs. Diphenhydramine can provide quick relief from acute symptoms of an allergic reaction, while prednisone can help control the underlying inflammation and prevent a recurrence of symptoms.

Benadryl is an antihistamine that typically works within 30 minutes of ingestion to relieve symptoms such as itching, hives, and sneezing. Because of its fast-acting nature, it is often used for immediate symptom relief.

Prednisone, on the other hand, is a corticosteroid that can take several hours to a day to start working, as it needs to be metabolized by the liver before it becomes active in the body. Its effects are more gradual because it reduces inflammation over time rather than providing immediate symptom relief.

Is it safe to take prednisone and Benadryl?

Generally, these two medications can be taken together as they work in different ways and do not typically interact in a harmful way. The safety of taking both medications often depends on the individual’s dosage, overall medical condition, and other medications they might be taking.

However, overdosing on corticosteroids like prednisone may lead to symptoms such as high blood pressure (hypertension), mood changes, muscle weakness, and increased thirst and urination. On the other hand, an overdose of Benadryl can cause symptoms of toxicity like confusion, blurred vision, dry mouth, and difficulty urinating. Always follow the recommended dosage of these medications and seek medical help immediately if an overdose is suspected.

Consult a healthcare professional before combining these medications, especially if you have pre-existing medical conditions or are taking other drugs, including OTC medicines and herbal supplements.

When to avoid prednisone and Benadryl

In some cases, it is not recommended to take prednisone or Benadryl. Avoid taking prednisone or Benadryl if any of the following apply:

Systemic fungal infections: Avoid prednisone if you have a systemic fungal infection, as it can worsen the infection.
Known allergies: Do not take prednisone or Benadryl if you have a known hypersensitivity to either drug or any of its inactive ingredients.
Live vaccines: Refrain from using prednisone if you are scheduled to receive a live or live-attenuated vaccine.
Acute asthma attacks: Benadryl should not be the primary treatment for acute asthma symptoms.
Neonates and premature infants: Benadryl is not recommended in neonates and premature infants due to an increased risk of side effects.
Nursing mothers: Benadryl is excreted in breast milk and may be contraindicated for breastfeeding mothers.
Narrow-angle glaucoma: Patients with narrow-angle glaucoma should avoid Benadryl, as it can worsen the condition.
Severe heart disease: Use Benadryl with caution in patients with severe heart disease, as antihistamines can cause a pounding or racing heart and an increase in blood pressure.
Psychiatric disorders: Caution is advised when using prednisone in individuals with psychiatric disorders, as it can worsen symptoms or lead to new mood disturbances.

In addition, it may be important to keep potential drug interactions in mind. Prednisone may interact with the following medications:

NSAIDs (nonsteroidal anti-inflammatory drugs): NSAIDs include medications like ibuprofen, aspirin, and naproxen. Using these with prednisone can increase the risk of gastrointestinal bleeding or ulcers.
Anticoagulants (blood thinners): Drugs such as warfarin and heparin can interact with prednisone, increasing the risk of bleeding complications.
Antibiotics: Some antibiotics like erythromycin, rifampin, and tetracycline may affect the metabolism of prednisone, altering its effectiveness and potentially leading to adverse effects.
Diuretics: Certain diuretics, such as furosemide or hydrochlorothiazide, can increase the risk of low potassium levels.
Antidiabetic drugs: Prednisone may affect blood sugar levels, requiring dosage changes of insulin or oral antidiabetic agents.

Benadryl may interact with the following medications:

Sedating medications: Sedating medications like opioids and benzodiazepines may increase side effects like dizziness and drowsiness.
Monoamine oxidase inhibitors (MAOIs): Drugs like phenelzine and tranylcypromine can lead to serious side effects, such as severe high blood pressure, when taken with Benadryl.
Antidepressants: Certain antidepressants, especially those with sedative effects like tricyclic antidepressants, can increase the risk of excessive drowsiness.
Anticholinergic drugs: Drugs that block acetylcholine, such as atropine or scopolamine, may increase Benadryl’s anticholinergic effects, amplifying certain side effects like dry mouth and urinary retention.
Alcohol: The sedative effects of Benadryl can be increased by alcohol.

It’s important to consult a healthcare provider before mixing prednisone and Benadryl, just like you would when taking each medication separately. This combination may only be safe under the guidance of a healthcare provider.